Impeller for centrifugal pump



April 9, 1957 INVENTOR. EDWARD lflSM/TH BY RIC/1E), WA 775, EDGERTO/VJM$NENNY A TTOENEYS United States Patent Olfice Patented Apr. 9, 1957IMPELLER FOR CENTRIFUGAL PUMP Edward M. Smith, Mansfield, Ohio, assignorto German- Rupp Industries, Inc., Bellville, Ohio, a corporation of OhioApplication January 4, 1954, Serial N 0. 401,841

3 Claims. (Cl. 103-103) This invention relates generally to centrifugalpumps and is particularly concerned with a new impeller for pumpingliquids containing fibers, threads and the like.

My co-pending application, Serial No. 179,767, filed August 16, 1950,now Patent No. 2,672,822, discloses a centrifugal pump equipped with animpeller including oppositely projecting, resilient, defiectable blades.it has been found that the efiiciency of pumps equipped with that typeof impeller has been maintained through a relatively Wide range ofoperation due to deflection of the blades but that fibers, threads,ravelings and the like which are often present in the water from washingmachines tend to wind around the impeller shaft and eventually to plugthe pump passages and prevent adequate flow of water. The presentinvention aims to retain the advantages and avoid the disadvantages ofthe prior impeller and attains that object by means of a new combinationof elements in which the elements act in cooperation to produce a newconjoint result which is different from that produced by the separateelements.

The present invention will be better understood by those skilled in theart from the following specification and the drawing accompanying andforming a part thereof, in which:

Fig. 1 is a central sectional view through a centrifugal pump embodyingthe present invention;

Fig. 2 is an elevational View of the impeller of Fig. 1 taken from thefluid inlet side;

Fig. 3 is an elevational view of the impeller of Figs. 1 and 2 showingthe blades in side elevation; and

Fig. 4 is an elevational View of the impeller of Figs. 1 and 2 showingthe blades in end elevation.

In Fig. l the pump shown comprises a housing 1 and a back plate 2. Thehousing 1 has a central inlet pipe 3 and a peripheral tangential outletpipe 4. The housing l and plate 2 define an impeller chamber 5 whichcommunicates with inlet pipe 3 and also with outlet pipe 4. An impelleris shown in chamber 5 with its shaft projecting through the back plateand through packing 11 carried by the back plate and surrounding theshaft 16 for preventing the passage of fluid out of the pump along shaft10.

The impeller of Fig. l is shown in more detail in Fig. 2, 3 and 4. Thisimpeller consists of a relatively inflexible disk and a resilient membercomprising an elongated hub is? having blades 17 extending therefromapproximately in opposite directions with edges or lips 18 which arequite flexible and bear against the adjacent surface of disk 15 whenassembled therewith. The hub 16 is provided with a shoulder 1? to bearagainst the other side of disk 15 and also has a projecting shaft it]which may be screw-threaded interiorly as at 21 for attachment to adrive shaft.

When the disk 15 is assembled with the hub and blades substantially asshown in Fig. 4, the flexible lips 18 of the blades 17 will initiallyengage snugly against the disk and will be pressed into closerengagement with the impeller, when it rotates, by reason of a pressureof water against the lips 18. During rotation of the impeller the freeends of the blade 17 may bend and move relative to the disk, that is,the water pressure exerted against the blades during their rotation maybend the blades backwardly to a limited extent. This flexing of theblades permits the impeller to conform to the pumping requirementswithout reducing the etficiency of the pumps or decreasing the snug fitbetween the blades and the disk. In this manner the blades may altertheir configuration under different pumping conditions and yet maintainthe efiiciency approximately constant at all tunes.

Since the disk is diametrically coextensive with the impeller there islittle, if any, tendency or opportunity for threads, ravelings, and thelike, to approach the hub 20 of the impeller and hence the previousdisadvantage of wrapping these objects around the impeller is avoided.This result follows from the fact that the water which enters theimpeller chamber through pipe 3 is immediately subjected to forcesdirecting it outwardly toward the periphery of the chamber anddischarging it tangential through pipe 4.

From the foregoing description it will be understood that the diskcooperates with the impeller blades to prevent threads, ravelings, andthe like, from coming into contact with shaft 20 of the impeller; and,also that the disk 15, blades 17 and lips 18 cooperate to maintain closefitting contact between the blades and disk While permitting limitedmovement of the blades relative to the disk under varying pumpingconditions without serious impairment of efiiciency.

Having thus described the present invention so that others skilled inthe art may be able to practice the same, I state that what I desire tosecure by Letters Patent is defined in What is claimed.

What is claimed is:

1. An impeller for a centrifugal pump comprising an elongated hub forattachment to a drive shaft, a shoulder on said hub, a disk surroundingsaid hub with one side bearing against said shoulder, blades ofresilient material extending outwardly from said hub and having flexiblelips extending longitudinally of the blades and pressing against theother surface of said disk and urging it against said shoulder.

2. An impeller for a centrifugal pump comprising an elongated hub forattachment to a drive shaft, a shoulder on said hub, a disk surroundingsaid hub with one side bearing against said shoulder, blades ofresilient material extending outwardly from said hub and having flexiblelongitudinal extending lips pressing against and distorted by contactwith the other surface of said disk, the outer ends of said blades beingbendable and movable to a limited extent relative to said'disk whilemaintaining the lips in contact with the disk.

3. A centrifugal pump comprising a housing defining an impeller chamberhaving inlet and outlet openings and an impeller rotatable in saidchamber, said impeller comprising an elongated hub for attachment to adrive shaft, a shoulder on said hub, a disk surrounding said hub withone side bearing against said shoulder, blades of resilient materialextending outwardly from said hub and having flexible longitudinallyextending lips pressing References Cited in the file of this patentUNITED STATES PATENTS Jandasek Aug. 27, 1946 Lehman July 7, 1953

